what's name of this construction？

there is a Ro-ro passenger，it has two propellers，the structure around the propeller is not casting parts，Part of the propeller shaft is located in the outer hull，Contain this part of the propeller shaft structure is called what？

I think he's referring to something like this (but not on a submarine) where the prop shaft exits the hull with no struts, no shaft logs etc. I think he wants to know what the prop shaft supporting/bearing/water sealing apparatus would be called in a description on a plan of a ship.

The Art of The Deal "You know what? It's yours, I'm leaving."
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"The best is not too good."

This was my interpretation of the Kalvens question. Years ago I was working in a shipyard on a 325' ro-ro ferry. I helped (briefly) the loftsman layout the plating rolling and forming templates for the shaft bossing.... quite a challenge.

Most believed struts would give the ship better performance, but Gibbs opted for enclosed (faired) shafts in bossings - even if they introduced undesired drag. He believed the bossings would better protect the drive line, given the demanding, constant high speed service requirements. Take a look at a very rare image below - revealing bossings and propeller placement.

Extensive model testing (collected by Gibbs between 1916 and 1950) revealed the best choice of design was a cruiser stern, very modest bulb and four shafts through bossings. (enclosed faired tail shafts) When comparing the Big U performance to new ship designs 50 years later, it turns out Gibbs & Cox engineers chose wisely.

Click to expand...

The Art of The Deal "You know what? It's yours, I'm leaving."
-------------------------------------------
"The best is not too good."

This was my interpretation of the Kalvens question. Years ago I was working in a shipyard on a 325' ro-ro ferry. I helped (briefly) the loftsman layout the plating rolling and forming templates for the shaft bossing.... quite a challenge.

Click to expand...

jsl: thank you for you raply, yeah~ it was this that i asked, quite right, it is shaft bossing.

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